Method of controlling a medication delivery system with a removable label containing instructions for setting medication delivery rate overlying a second label with patient instructions

ABSTRACT

A method of controlling a medication delivery system is used to deliver medication to a patient. The system includes an electronic controller, at least one control button, a patient label, and a removable overlay label disposed on top of the patient label for controlling an amount of the medication to be delivered to the patient. The method comprises the steps of selecting the amount of the medication in accordance with a first set of explanatory indicia on the removable overlay label; locking the system such that the selected amount of the medication to be delivered to the patient is unable to be modified; removing the removable overlay label to reveal the patient label; and operating the system in accordance with a second set of explanatory indicia on the patient label.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/701,207, filed Nov. 4, 2003, which is a continuation of U.S. patentapplication Ser. No. 10/083,266, filed on Feb. 23, 2002, now U.S. Pat.No. 6,679,862, which claims priority to U.S. Provisional PatentApplication No. 60/271,187, filed on Feb. 23, 2001. The advantages anddisclosures of each of the aforementioned applications are herebyincorporated by reference.

FIELD OF THE INVENTION

The subject invention generally relates to a method of controlling amedication delivery system and, more specifically, a method ofcontrolling a medication system that is used to deliver medication to apatient wherein the system includes an electronic controller.

BACKGROUND OF THE INVENTION

Medication delivery systems are known in the art. As indicated above,medication delivery systems are used to deliver pain control medicationand other medications intra-operatively, subcutaneously, andpercutaneously to a patient after a surgical, or some other medical,procedure.

Conventional medication delivery systems are deficient for one reason oranother. For example, U.S. Pat. No. 5,807,075 to Jacobsen et al.discloses a conventional medication delivery system that includes a basehousing and a cassette. The base housing of the '075 patent houseselectronic components, such as an electric motor, a power source, and anelectronic controller, and the cassette of the '075 patent interactswith a supply of the medication to deliver the medication to thepatient. This medication delivery system is deficient because the supplyof the medication is not integrated into the cassette. That is, thecassette does not house the supply of the medication. Instead, thesupply is external to the medication delivery system. This medicationdelivery system is also deficient because the base housing and thecassette are not properly integrated. As such, the complete medicationdelivery system, having the base housing and the cassette, cannot besimultaneously sterilized prior to use of the system. Instead, the basehousing and the cassette require separate sterilization. Furthermore,because the base housing and the cassette are not integrated, thecassette must be mounted to the base housing which requires additionalassembly by a surgeon or some other medical assistant. This additionalassembly is time consuming and is often inconvenient for the surgeonsand medical assistants.

A further example of a conventional medication delivery system isdisclosed in U.S. Pat. No. 4,650,469 to Berg et al. This patentdiscloses a medication delivery system that includes a control moduleand a reservoir module removably connected to the control module. Thecontrol module includes a pump mechanism, valves, a power source,electronic controls, and the like, and the reservoir module includes acontainer that supplies the medication to be delivered to the patient.Although the medication delivery system disclosed in the '469 patentconnects the control module and the reservoir module, this medicationdelivery system is deficient in that, once connected, the control moduleand the reservoir module cannot be simultaneously sterilized. Themodules cannot be simultaneously sterilized because, as described atcolumn 11, lines 22-28, one of the valves in the control module closesthe fluid connection (the tube 22) between the control module and thereservoir module at all times. That is, the '469 patent does not includea device, such as an actuator, to prevent the valves from closing onthis fluid connection. As such, a sterilization fluid, such as ethyleneoxide (EtO) gas cannot flow into both the control module and thereservoir module once these modules are connected.

The conventional medication delivery system disclosed in the '469 patentis also deficient because it relies exclusively on a motor and a camshaft to move the valves from the open position to the closed positionwhen delivering the medication to the patient. This medication deliverysystem does not incorporate an additional biasing device to ensure thatthe valves are biased into the closed position if the motor, gear, camshaft, or power supply fails. Without such an additional biasing device,this system's ability to prevent the inadvertent delivery of themedication to the patient in the event of one of the above failures iscompromised. Instead, this medication delivery system relies only on themotor and the cam shaft to allow or to prevent delivery of themedication, and reliance on these two components is insufficient.

Other conventional medication delivery systems are also deficient for amultitude of other reasons. For instance, these conventional systems donot incorporate port assemblies that adequately control the flow ofmedication throughout the system. In these conventional systems, asingle port assembly does not enable various medical fluids to flowinto, from, and within the system. Conventional medication deliverysystems also do not provide detection systems that adequately determinewhen a medication delivery system is realizing a blockage in the flow ofmedication to the patient or that adequately determine when a supply inthe medication delivery system has been depleted. The detection systemsin the prior art medication delivery systems do not make optimum use ofthe position of the tubes that carry the medication relative to theposition of the electronic controller. Conventional medication deliverysystems also do not provide a testing access port that allowsmanufacturers to confirm operation of the medication delivery systemafter assembly, and prior to use, of the system. As such, the operationof many prior art medication delivery systems cannot be confirmed priorto shipment to medical professionals for use. Conventional medicationdelivery systems are also not ideal for carrying. Some prior art systemsdo not even include a carrying strap. As such, the patient cannot beeasily treated outside of a hospital or other medical facility, thepatient is prevented from being ambulatory. Other medication deliverysystems in the prior art that do include some form of carrying strap donot make carrying convenient because, in these systems, the carryingstrap is not conveniently stored in a storage cavity of the system. Thatis, the carrying strap is not integrated into the system itself for easyaccess by the patient. The medication delivery systems of the prior artare also not easily controlled. That is, there is not method associatedwith these systems that effectively controls an amount of the medicationto be delivered to the patient. The prior art methods for controllingthe amount of medication that is to be delivered to the patient aredeficient because these methods require constant attention, requirecomplicated set-up and monitoring by the surgeon or other medicalprofessional, and may even risk the health and safety of the patient.Other conventional medication delivery systems do not have electroniccontrollers, specifically specialized circuitry incorporated into thecontroller, that adequately prevent too much medication from beingdelivered to the patient in the event of failure of certain mechanicalcomponents. Also, the electronic controllers and circuitry of otherconventional medication delivery systems are not suitably designed tomaximize the conservation of power and to prevent the entire medicationdelivery system from being reset by removing and replacing the powersource, e.g. a battery.

Due to the deficiencies in conventional medication delivery systems,including those described above, it is desirable to provide a novelmedication delivery system that is appropriately integrated forsimultaneous sterilization. It is also desirable to provide a novelmedication delivery system that overcomes the other deficienciesidentified above in the prior art.

SUMMARY OF THE INVENTION AND ADVANTAGES

The present invention includes a method of controlling a medicationdelivery system that is used to deliver medication to a patient whereinthe system includes an electronic controller, at least one controlbutton, a patient label, and a removable overlay label disposed on topof the patient label for controlling an amount of the medication to bedelivered to the patient. The method comprises the steps of

selecting the amount of the medication in accordance with a first set ofexplanatory indicia on the removable overlay label; locking the systemsuch that the selected amount of the medication to be delivered to thepatient is unable to be modified; removing the removable overlay labelto reveal the patient label; and operating the system in accordance witha second set of explanatory indicia on the patient label. The subjectinvention overcomes the deficiencies in the prior art, including thosedescribed above.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1A is a perspective view of an integrated medication deliverysystem according to the subject invention with an infusion tube set;

FIG. 1B is a perspective view of an underside of the system illustratinga system mounting clip for securing the system to a patient;

FIG. 2A is an exploded perspective view of the system illustrating amedication reservoir, a base housing, reservoir casings, a pumpassembly, and a carrying strap of the system;

FIG. 2B is an exploded perspective view of the system illustrating aremovable overlay label, a patient label, and a top housing of the basehousing for assembly to the system;

FIG. 3 is an exploded perspective view of the system illustrating aport, a plunger, the pump assembly including a motor and first andsecond pinch levers, an actuator, and the base housing including anintegral storage cavity for the carrying strap;

FIG. 4 is an exploded perspective view of the system illustrating anunderside of the top housing, at least one control button, an electroniccontroller and display, and a detection film having a cantileverportion;

FIG. 5 is an exploded perspective view of the pump assembly;

FIG. 6A is a partially cross-sectional side view of a cam shaft, thepump assembly, and the first and second pinch levers illustrating thepinch levers in a closed position to pinch medication inlet and outlettubes;

FIG. 6B is a partially cross-sectional side view of the system, asdisclosed in FIG. 6A, illustrating the first pinch lever in an openposition and the second pinch lever in a closed position to drawmedication into the pump assembly;

FIG. 6C is a partially cross-sectional side view of the system, asdisclosed in FIG. 6A, illustrating the first pinch lever in a closedposition and the second pinch lever in an open position to displacemedication from the pump assembly;

FIG. 6D is a partially cross-sectional side view of the system, asdisclosed in FIG. 6A, in combination with the plunger and the actuator,with the actuator retaining the pinch levers in the open position;

FIG. 7 is a partially cross-sectional side view of the pump assembly;

FIG. 8 is an exploded perspective view of the port and the plunger;

FIG. 9 is an enlarged partially cross-sectional top view of the plungerdisposed in the port illustrating a first, second, and third fluidconnector;

FIG. 10 is a partially cross-sectional side view taken along line 10-10in FIG. 9 illustrating a seal disposed about the plunger being depressedby leak ribs extending from the port;

FIG. 11A is a partially cross-sectional top view of the system with theplunger in an off-position;

FIG. 11B is a partially cross-sectional view of the port and the plungerdisposed in the port in the off-position from FIG. 11A;

FIG. 12A is a partially cross-sectional top view of the system with theplunger in a fill-position such that the system can be sterilized andfilled with medication;

FIG. 12B is a partially cross-sectional view of the port and the plungerdisposed in the port in the fill-position from FIG. 12A additionallyillustrating a syringe for moving the plunger into the fill-position anda fluid cap for sterilization;

FIG. 13A is a partially cross-sectional top view of the system with theplunger in a fluid delivery-position such that the medication can bedelivered to the patient;

FIG. 13B is a partially cross-sectional view of the port and the plungerdisposed in the port in the fluid delivery-position from FIG. 13Aadditionally illustrating a connector from the infusion tubing set;

FIG. 14A is an enlarged perspective view of the actuator;

FIG. 14B is a perspective view of an alternative embodiment for theactuator including a control contact disposed at a distal end of anactuation arm;

FIG. 15A is a partially cross-sectional side view of a blockagedetection system according to the subject invention when the medicationoutlet tube is in a normal condition;

FIG. 15B is a partially cross-sectional side view of the blockagedetection system of FIG. 15A when the medication outlet tube is in anexpanded condition due to a blockage;

FIG. 16A is a partially cross-sectional side view of an empty detectionsystem according to the subject invention when the medication inlet tubeis in a normal condition;

FIG. 16B is a partially cross-sectional side view of the empty detectionsystem of FIG. 16A when the medication inlet tube is in a collapsedcondition due to a depletion in the supply of the medication;

FIG. 17 is a perspective view of a support platform with the medicationinlet and outlet tubes which also illustrates alternative embodimentsfor the blockage detection system and the empty detection system where acoating is applied to the medication inlet and outlet tubes;

FIG. 18A is a top perspective view of the system engaged with a testinginstrument for confirming proper operation of the system after assemblyand prior to use;

FIG. 18B is a bottom perspective view of the system engaged with asecond testing instrument for confirming proper operation of the systemafter assembly and prior to use;

FIG. 19 is a perspective view of the patient using the carrying strap asa shoulder strap to carry the system;

FIG. 20 is an enlarged top perspective view of the integral storagecavity defined within the base housing of the system;

FIG. 21 is a perspective view of a surgeon or patient removing theremovable overlay label to reveal the patient label;

FIG. 22 is a plan view of one embodiment of the removable overlay labelhaving a one version of a first set of explanatory indicia;

FIG. 23 is a plan view of a further embodiment of the removable overlaylabel having another version of a first set of explanatory indicia;

FIG. 24 is a plan view of the patient label having a second set ofexplanatory indicia;

FIG. 25 is a block diagram schematically illustrating a control systemfor the integrated medication delivery system of the subject invention;

FIG. 26 is an electrical diagram illustrating portions of a watchdogcircuit of the control system; and

FIG. 27 is an electrical diagram illustrating further portions of thewatchdog circuit of the control system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the Figures, wherein like numerals indicate like orcorresponding parts throughout the several views, an integratedmedication delivery system 10 is generally disclosed at 10. Theintegrated medication delivery system 10, hereinafter described as thesystem 10, delivers medication to a patient 12 (refer to FIG. 19). Morespecifically, the system 10 is primarily used throughout the medicalprofession to deliver pain control medication and other medications tothe patient 12 after a surgical, or some other medical, procedure. Asdisclosed in FIG. 1A, the system 10 is used in combination with aninfusion tube set 14 to deliver the medication to the patient 12. Theinfusion tube set 14 is described below.

The system 10 of the subject invention is also suitable for completesterilization by a sterilization fluid including, but not limited to,ethylene oxide (EtO) gas. Although not ideal, certain liquids may evenbe used to sterilize the system 10. For descriptive purposes only, theterminology of “medication” and of “sterilization” fluid may also bedescribed throughout simply as a fluid.

Referring primarily to FIGS. 2A-3, the system 10 includes a base housing16. The base housing 16 is further defined as a bottom housing 18, amiddle housing 20 mounted to the bottom housing 18 and a top housing 22,i.e., a cover. The housings 18, 20, 22 are preferably mounted togethervia screws 23. The system 10 also includes a medication reservoir 24disposed about the base housing 16. More specifically, the reservoir 24is disposed about the middle housing 20. The reservoir 24 stores thesupply of medication that is to be delivered to the patient 12.Preferably, the reservoir 24 is formed of a flexible, yet durableplastic material. The system 10 further includes a reservoir casing 26disposed between the bottom and top housings 18, 22. The reservoircasing 26 at least partially surrounds the reservoir 24 to protect themedication that is to be delivered to the patient 12. The preferredembodiment of the subject invention includes two reservoir casings 26that surround the reservoir 24 to protect the medication. Of course, itis to be understood that the reservoir casing 26 may be a unitarycomponent and still adequately surround the reservoir 24 to protect themedication. The reservoir casing 26 is particularly useful when thepatient 12 is carrying the system 10. Carrying of the system 10 isdescribed below.

Referring primarily to FIGS. 2A, 3, and 5-6D, a pump assembly 28 issupported by the base housing 16. Specifically, the pump assembly 28 ismounted to the bottom housing 18. As understood by those skilled in theart, the pump assembly 28 is responsible for delivering the medicationto the patient 12. As described below, the pump assembly 28 also servesto prevent inadvertent delivery of the medication to the patient 12.

As disclosed best in FIG. 5, the pump assembly 28 includes a pumphousing 30 having a pump inlet 32 and a pump outlet 34. The pump housing30 also has at least one detent 36. The at least one detent 36 isdescribed below. The pump inlet 32 and the pump outlet 34 alternatebetween an open and a closed state to deliver the medication to thepatient 12. Referring now to FIGS. 3, and 6A-6D, a first pinch lever 38,also referred to as a pinch valve, is disposed at the pump inlet 32 anda second pinch lever 40 or valve is disposed at the pump outlet 34. Thefirst pinch lever 38 functions to alternate the pump inlet 32 betweenthe open and the closed state, and the second pinch lever 40 functionsto alternate the pump outlet 34 between the open and the closed state.

As FIGS. 6B and 6C disclose, the first pinch lever 38 is moveablebetween an open position (FIG. 6B) and a closed position (FIG. 6C) tocontrol a flow of the medication into the pump housing 30 through thepump inlet 32, and the second pinch lever 40 is moveable between an openposition (FIG. 6C) and a closed position (FIG. 6B) to control a flow ofthe medication from the pump housing 30 through the pump outlet 34. Thepump assembly 28 further includes a motor 42 that is operatively engagedto the first and second pinch levers 38, 40 for moving these levers 38,40 into the open position such that the medication can be delivered tothe patient 12. The motor 42 includes a driving output shaft, not shownin the Figures, for driving the pump assembly 28. A power source 43 isintegrated into the system 10 to provide power to the system 10,including the motor 42. Preferably, the power source includes batteries45 and battery contacts 47.

As shown in FIG. 6A, the first pinch lever 38 is normally-biased tomaintain the pump inlet 32 in the closed state and the second pinchlever 40 is normally-biased to maintain the pump outlet 34 in the closedstate. To accomplish this, at least one biasing device 44 is included inthe pump assembly 28. Preferably, the at least one biasing device 44 isa compression spring as shown, but not numbered, throughout the Figures.However, it is to be understood that the at least one biasing device 44may be any device that is suitable for normally-biasing at least one, ifnot both, of the first and second pinch levers 38, 40 into the closedposition. The at least one biasing 44 device engages at least one of thefirst and second pinch levers 38, 40 and works in conjunction with themotor 42 to normally bias at least one of the first and second pinchlevers 38, 40 into the closed position. As such, if the motor 42 failsduring delivery of the medication, then the first and second pinchlevers 38, 40 are biased into and thereafter maintained in the closedposition to prevent the inadvertent delivery of the medication to thepatient 12. The motor 42 is able to move the first and second pinchlevers 38, 40 into the open position despite the bias of the at leastone biasing device 44.

In the preferred embodiment of the subject invention, the at least onebiasing device 44 comprises a first 46 and a second 48 biasing device.The first biasing device 46, preferably a compression spring, engagesthe first pinch lever 38, and the second biasing device 48, alsopreferably a compression spring, engages the second pinch lever 40. Asdisclosed in FIG. 6A, the first and second biasing devices 46, 48maintain the first and second pinch levers 38, 40 in the closed positionduring failure of the motor 42 thereby preventing the inadvertentdelivery of the medication to the patient 12. More specifically, theclosed first pinch lever 38 prevents the medication from being drawninto the pump assembly 28 through the pump inlet 32, and the closedsecond pinch lever 40 prevents the medication from being displaced fromthe pump assembly 28 through the pump outlet 34.

Referring primarily to FIGS. 5-6D, to effectively operate the system 10and move the first and second pinch levers 38, 40 for delivery of themedication to the patient 12, the pump assembly 28 of the subjectinvention further includes a cam shaft 50 supported on the pump housing30. The cam shaft 50 is geared to the motor 42, via a number of gears52, to operatively engage the motor 42 to the first and second pinchlevers 38, 40. The cam shaft 50 is described in greater detail below.

As disclosed best in FIGS. 5 and 7, the pump assembly 28 also includes apiston 54 disposed in the pump housing 30. The motor 42 moves the piston54 within the pump housing 30 to draw the medication into the pumphousing 30 when the first pinch lever 38 is in the open position and thesecond pinch lever 40 is in the closed position (see FIG. 6B). The motor42 also moves the piston 54 within the pump housing 30 to displace themedication from the pump housing 30 when the first pinch lever 38 is inthe closed position and the second pinch lever 40 is in the openposition (see FIG. 6C). The piston 54 includes an actuation end 56 and apumping end 58. A diaphragm seal 60 is disposed at the pumping end 58 ofthe piston 54. The diaphragm seal 60 is secured at the pumping end 58 ofthe piston 54 by a piston cap 62. Piston cap 62 seats in an enclosedvoid defined by the pump housing 30 between the inlet 32 and pump outlet34 that is a pump chamber 33. The piston 54 also includes at least oneslot 61 at the actuation end 56. The at least one detent 36 of the pumphousing 30, originally introduced above, engages the at least one slot61 at the actuation end 56 of the piston 54 to prevent unwanted rotationof the piston 54 as the piston 54 is moved within the pump housing 30 bythe motor 42 and the cam shaft 50.

The cam shaft 50 supports first and second outside cams 64, 66 and aninside cam 68. The inside cam 68 of the cam shaft 50 is disposed betweenthe first and second outside cams 64, 66. The first outside cam 64engages the first pinch lever 38 to move the first pinch lever 38between the open and closed position, and the second outside cam 66engages the second pinch lever 40 to move the second pinch lever 40between the open and closed positions. The inside cam 68 engages theactuation end 56 of the piston 54 to move the piston 54 within the pumphousing 30.

Referring to FIG. 5, the first and second outside cams 64, 66 include aplurality of slits 70 along an outer circumference 72 of the cams 64,66. These slits 70 are used during assembly and testing of the system 10to confirm dimensional tuning of the cams 64, 66. Also, at least one ofthe first and second outside cams 64, 66, preferably the first outsidecam 64, includes an assembly slot 74 defined within the outercircumference 72 of the cams 64, 66. This assembly slot 74 facilitatesassembly of the pump assembly 28. In particular, this assembly slot 74facilitates mounting of the cam shaft 50, including the cams 64, 66,after the first and second pinch levers 38, 40 have already beenincorporated into the system 10.

Each of the first and second pinch levers 38, 40 comprise a cam follower76 and lever guides 78. The lever guides 78 are described below. The camfollowers 76 of the pinch levers 38, 40 are engaged by the cam shaft 50for alternating movement of the first and second pinch levers 38, 40between the open and closed positions such that the medication can bedelivered to the patient 12. More specifically, the cam follower 76 ofthe first pinch lever 38 is engaged by the first outside cam 64 foralternating movement of the first pinch lever 38 between the open andclosed positions, and the cam follower 76 of the second pinch lever 40is engaged by the second outside cam 66 for alternating movement of thesecond pinch lever 40 between the open and closed positions. Even morespecifically, each of the first and second outside cams 64, 66 includeinternal cam surfaces 80. As disclosed in FIGS. 6A-6D, the cam follower76 of the first pinch lever 38 rides within the internal cam surface 80of the first outside cam 64 for alternating movement of the first pinchlever 38, and the cam follower 76 of the second pinch lever 40 rideswithin the internal cam surface 80 of the second outside cam 66 foralternating movement of the second pinch lever 40.

Referring primarily to FIGS. 3, and 8-10, the system 10 further includesa port assembly 82 that enables various fluids, such as the medicationor the sterilization fluid, to flow into, from, and within the system10. The port assembly 82, hereinafter described as the port 82, extendsfrom the base housing 16. More specifically, the port 82 extends fromthe middle housing 20. The port 82 is in fluid communication with thereservoir 24 and the pump assembly 28. During sterilization, the port 82provides access for the sterilization fluid to flow into the reservoir24 and the pump assembly 28. During filling, the port 82 provides accessfor the medication to flow into the reservoir 24 and the pump assembly28. During delivery of the medication to the patient 12, the port 82provides access for the medication to be delivered to the patient 12.

Referring particularly to FIGS. 9, and 11A-13B, the port 82 includes anelongated housing 84. The elongated housing 84 includes a proximate end86, a distal end 88, and an interior wall 90 defining a fluid chamber 92between the proximate and distal ends 86, 88. It is the proximate end 86of the elongated housing 84 that extends from the system 10 to provideaccess for the fluid to flow both into and from the system 10. The port82 further includes a first fluid connector 94, a second fluid connector96, and a third fluid connector 98. The first fluid connector 94,alternatively referred to as an outlet of the port 82, extends from theelongated housing 84 to allow the fluid to flow from the fluid chamber92 into the pump assembly 28. The second fluid connector 96,alternatively referred to as an inlet to the port 82, extends from theelongated housing 84 to allow the fluid to flow from the pump assembly28 into the fluid chamber 92. The third fluid connector 98,alternatively referred to as an access to the reservoir 24, extends fromthe elongated housing 84 to allow the fluid to flow between the fluidchamber 92 and the reservoir 24. In the preferred embodiment of thesubject invention, there are two third fluid connectors 98, one thirdfluid connector 98 extending from opposite sides of the elongatedhousing 84.

Referring primarily to FIGS. 3, 6D, 8-10, and 11A-13B, the port 82further includes a plunger 100. The plunger 100 is disposed in the fluidchamber 92 of the port 82 and is moveable between an off-position (FIGS.11A-11B), a fill-position (FIGS. 12A-12B), and a fluid delivery-position(FIGS. 13A-13B). As disclosed in FIGS. 11A-11B, in the off-position, thefirst, second, and third fluid connectors 94, 96, 98 are isolated fromthe proximate end 86 of the elongated housing 84 by the plunger 100. Asa result, the flow of fluid through the port 82 is prevented. Asdisclosed in FIGS. 12A-12B, in the fill-position, the first and thirdfluid connectors 94, 98 are in fluid communication with the proximateend 86 of the elongated housing 84. As a result, a fluid flow path,shown but not numbered in FIGS. 12A-12B, is provided between theproximate end 86 of the elongated housing 84, the medication reservoir24, and the pump assembly 28 such that the fluid can be filled throughthe proximate end 86 of the housing and into the medication reservoir 24and the pump assembly 28. This fluid flow path is defined between theport 82, the reservoir 24, and the pump assembly 28 such that the flowof sterilization fluid through the fluid flow path is continuous duringsterilization of the system 10. The fill-position of the plunger 100 isutilized when the system 10 is being sterilized with the sterilizationfluid and also when the system 10 is being filled with medication. Asdisclosed in FIGS. 13A-13B, in the fluid delivery position, the first,second, and third fluid connectors 94, 96, 98 are in fluid communicationwith the proximate end 86 of the elongated housing 84 and with eachother for supplying the pump assembly 28 and for delivering the fluid tothe patient 12.

Referring primarily to FIGS. 3, 6D, 11A, 12A, 13A, and 14A-14B, thesystem 10 further includes an actuator 102 disposed in the base housing16. The actuator 102 is moveable between a disengaged position and anengaged position. The disengaged position of the actuator 102 isdescribed below. As disclosed in FIG. 6D, in the engaged position, theactuator 102 operatively engages the pump inlet 32 and the pump outlet34 to retain, i.e., lock, both the pump inlet 32 and the pump outlet 34in the open state during sterilization. With the pump inlet 32 and thepump outlet 34 in the open state, the sterilization fluid can penetratethroughout the entire system 10 to completely sterilize the system 10.That is, the sterilization fluid can penetrate into the reservoir 24,the pump inlet 32, the pump housing 30, and the pump outlet 34 tocompletely sterilize the system 10.

More specifically, the actuator 102 interacts with the first and secondpinch levers 38, 40 to retain both the pump inlet 32 and the pump outlet34 in the open state during sterilization. In the engaged position, theactuator 102 moves the first pinch lever 38 away from the pump inlet 32into the open position to retain the pump inlet 32 in the open state,and the actuator 102 moves the second pinch lever 40 away from the pumpoutlet 34 into the open position to retain the pump outlet 34 in theopen state. The actuator 102 retains both the first and second pinchlevers 38, 40 in the open position for sterilization despite the bias ofthe at least one biasing device 44.

On the other hand, when the actuator 102 is in the disengaged position,as indicated by the absence of the actuator 102 from FIGS. 6B-6C, theactuator 102 is operatively disengaged from the pump inlet 32 and thepump outlet 34. The actuator 102 is in the disengaged position when itis necessary to deliver the medication to the patient 12 such that thepump inlet 32 and the pump outlet 34 can alternate between the open andclosed states to deliver the medication the patient 12. Disengagement ofthe actuator 102 permits the pump inlet 32 and the pump outlet 34 toalternate between the open and closed states.

Referring particularly to FIGS. 14A-14B, the actuator 102 is disclosedin greater detail. The actuator 102 is in the form of a rigid body thatincludes an elongated, rod-like, base portion 104. At least oneengagement arm 106 extends from the base portion 104. The at least oneengagement arm 106 of the actuator 102 operatively engages the pumpassembly 28 to retain the pump inlet 32 and the pump outlet 34 in theopen state during sterilization. In the preferred embodiment of thesubject invention, the actuator 102 more specifically includes first andsecond engagement arms 108, 110, respectively, extending from the baseportion 104. In the preferred embodiment, the actuator 102 also includesan actuation arm 112. The actuation arm 112 extends from the baseportion 104 between the first and second engagement arms 108, 110. Asshown in the Figures, the actuation arm 112 extends upwardly from thebase portion 104 between the first and second engagement arms 108, 110.

During sterilization, the first engagement arm 108 of the actuator 102engages the first pinch lever 38 to move the first pinch lever 38 awayfrom the pump inlet 32 to retain the pump inlet 32 in the open state.Similarly, during sterilization, the second engagement arm 110 of theactuator 102 engages the second pinch lever 40 to move the second pinchlever 40 away from the pump outlet 34 to retain the pump outlet 34 inthe open state.

After sterilization it is desirable to move the actuator 102 into thedisengaged position such that the pump assembly 28 can operate and themedication can be delivered to the patient 12. As indicated by the arrow(A) in FIG. 6D, the plunger 100 moves to displace the actuator 102 fromthe engaged position thereby moving the actuator 102 into the disengagedposition. To displace the actuator 102, the plunger 100 engages theactuation arm 112. The plunger 100 displaces the actuator 102 from theoperative engagement with the pump assembly 28 after sterilization suchthat the pump inlet 32 and the pump outlet 34 can alternate between theopen and the closed state to deliver the medication to the patient 12.More specifically, the plunger 100 displaces the actuator 102 from theengagement with the first and second pinch levers 38, 40 aftersterilization such that medication can be delivered to the patient 12.As such, the motor 42, which is operatively engaged to the first andsecond pinch levers 38, 40, can move these levers 38, 40 for drawing themedication into the pump housing 30 through the pump inlet 32 and fordisplacing the medication from the pump housing 30 through the pumpoutlet 34.

Referring now to FIG. 14B, a control contact 114, preferably aspring-like control contact 114, may be disposed at a distal end 116 ofthe actuation arm 112 away from the base portion 104 to indicate to thesystem 10 whether the actuator 102 is in the engaged or the disengagedposition. The control contact 114 interacts with the actuation arm 112of the actuator 102 upon the movement of the actuator 102 between theengaged or the disengaged position. If the control contact 114 isincluded, it is preferred that when the actuator 102 is disengaged fromthe first and second pinch levers 38, 40, i.e., when the actuator 102 isin the disengaged position, it contacts the control contact 114 toactive an electronic controller 118. The electronic controller 118 isactivated to permit the pump assembly 28 to operate for delivering themedication to the patient 12. As indicated above, it is preferred thatthe actuation arm 112 of the actuator 102 is in contact with the controlcontact 114 when the actuator 102 is in the disengaged position. Ofcourse, it is to be understood that the opposite could be true. That is,the system 10 can be designed such that the actuation arm 112 of theactuator 102 is in contact with the control contact 114 when theactuator 102 is in the engaged position.

The system 10 further includes a medication inlet tube 120 and amedication outlet tube 122. The medication inlet tube 120 is connectedbetween the port 82 and the pump inlet 32 to provide access for thesterilization fluid to flow from the port 82 into the pump assembly 28,specifically into the pump inlet 32. The medication outlet tube 122 isconnected between the pump outlet 34 and the port 82 to provide accessfor the sterilization fluid to flow from the pump assembly 28,specifically from the pump outlet 34, into the port 82. The medicationinlet tube 120 and the first pinch lever 38 together establish the pumpinlet 32, and the medication outlet tube 122 and the second pinch lever40 together establish the pump outlet 34.

When the at least one biasing device 44 engages the first pinch lever 38to normally-bias the first pinch lever 38 into the closed position, themedication inlet tube 120 is pinched. As such, the pump inlet 32 ismaintained in the closed state. Similarly, when the at least one biasingdevice 44 engages the second pinch lever 40 to normally-bias the secondpinch lever 40 into the closed position, the medication outlet tube 122is pinched. As such, the pump outlet 34 is maintained in the closedstate. However, as disclosed in FIG. 6D, when the actuator 102 is in theengaged position during sterilization, the actuator 42 overcomes thebias of the at least one biasing device 44 to move the first pinch lever38 away from the medication inlet tube 120 such that the pump inlet 32remains in the open state, and the actuator 102 overcomes the bias ofthe at least one biasing device 44 to move the second pinch lever 40away from the medication outlet tube 122 such that the pump outlet 34remains in the open state.

Referring particularly to FIGS. 3, and 8-10, the port 82 and the plunger100 are described in greater detail. The plunger 100 includes a lengthL, a circumference C, and a plurality of seats 124 disposed along thelength L and about the circumference C of the plunger 100. The seats 124extend outwardly from the circumference C of the plunger 100 to theinterior wall 90 of the elongated housing 84 of the port 82 to segregatethe fluid chamber 92 of the elongated housing 84. A fluid passage, notnumbered, is defined between each of the seats 124 and the interior wall90 of the housing. These fluid passages control the flow of fluid withinthe port 82. Although the seats 124 may suitably segregate the fluidchamber 92, it is preferred that seals 126 are disposed about each ofthe seats 126 to assist with sealing the fluid passages from oneanother. In the most preferred embodiment, which is shown in theFigures, these seals are O-rings. At least one leak rib 128 extends atleast partially along the interior wall 90 of the elongated housing 84.The at least one leak rib 128 selectively causes at least one of theseals 126 to leak when the plunger 100 is in the fill-position. Asdisclosed in the Figures, preferably there are two leak ribs 128 thatextend along the interior wall 90 of the elongated housing 84.

As shown in FIGS. 11A-13B, the plunger 100 is at least partially hollow.As such, the plunger 100 defines an internal fluid bore 130 that extendswithin the plunger 100 between the seats 124. The plunger 100 furtherincludes an access end 132 and a plunger actuation end 134. A plungerbiasing device 136, preferably a compression spring, is disposed aboutthe plunger actuation end 134 of the plunger 100 to bias the plunger 100into the off-position. The internal fluid bore 130 extends from theaccess end 132, where the fluid flows into and from the internal fluidbore 130, toward the plunger actuation end 134. The internal fluid bore130 includes a fluid duct 138 in fluid communication with one of thefluid passages such that the flow can flow into and from the internalfluid bore 130.

In the most preferred embodiment of the subject invention, the pluralityof seats 124 are further defined as a first, second, third, and fourthseat 140, 142, 144, 146, respectively. The first seat 140 is disposedtoward the access end 132 of the plunger 100, the fourth seat 146 isdisposed toward the plunger actuation end 134 of the plunger 100, andthe second and third seats 142, 144 are disposed successively betweenthe first and fourth seats 140, 146. In this embodiment, the fluidpassages are further defined as a first, second, and third fluid passage148, 150, 152, respectively. The first fluid passage 148 is definedbetween the first and second seats 140, 142 and the interior wall 90,the second fluid passage 150 is defined between the second and thirdseats 142, 144 and the interior wall 90, and the third fluid passage 152is defined between the third and fourth seats 144, 146 and the interiorwall 90.

A first seal 154 is disposed about the first seat 140 for sealing thefirst fluid passage 148 from the access end 132 of the plunger 100, asecond seal 156 is disposed about the second seat 142 for sealing thefirst and second fluid passages 148, 150 from one another, a third seal158 is disposed about the third seat 144 for sealing the second andthird fluid passages 150, 152 from one another, and a fourth seal 160 isdisposed about the fourth seat 146 for sealing the third fluid passage152 from the plunger actuation end 134 of the plunger 100. In thisembodiment, the at least one leak rib 128 extends along the interiorwall 90 of the elongated housing 84 from the proximate end 86 toward thedistal end 88 just beyond the first seal 154 such that only the firstseal 154 selectively leaks when the plunger 100 is in the fill-position.

In this most preferred embodiment, the internal fluid bore 130 extendswithin the plunger 100 from the access end 132 to the third seat 144. Assuch, the fluid duct 138 is in fluid communication with the second fluidpassage 150 defined between the second and third seats 142, 144 and theinterior wall 90 such that the fluid can flow into and from the internalfluid bore 130 at the second fluid passage 150.

The off-, fill-, and fluid delivery-positions of the plunger 100 are nowdescribed in the context of this most preferred embodiment having fourseats 140, 142, 144, 146, three fluid passages 148, 150, 152, and fourseals 154, 156, 158, 160. Referring to FIGS. 11A-11B, when the plunger100 is in the off-position, the first, second, and third fluidconnectors 94, 96, 98 are isolated from the proximate end 86 of theelongated housing 84 and from the access end 132 of the plunger 100 bythe first, second, and third seats 140, 142, 144. In this off-position,the first and third fluid connectors 94, 98 are aligned with the thirdfluid passage 152.

Referring to FIGS. 12A-12B, when the plunger 100 is in thefill-position, the first and third fluid connectors 94, 98 are in fluidcommunication with the proximate end 86 of the elongated housing 84 andwith the access end 132 of the plunger 100 through the second fluidpassage 150 and the fluid duct 138 of the internal fluid bore 130. Inthis fill-position, the first and third fluid connectors 94, 98 arealigned with the second fluid passage 150. As such, the fluid can befilled through the access end 132 of the plunger 100, through theinternal fluid bore 130 and the fluid duct 138, and into the reservoir24 and the pump assembly 28. In the fill-position, the second fluidconnector 96 is isolated from the proximate end 86 of the elongatedhousing 84, from the access end 132 of the plunger 100, and from thefirst and third fluid connectors 94, 98 by the third and fourth seats144, 146.

Referring to FIGS. 13A-13B, when the plunger 100 is in the fluiddelivery-position, the second fluid connector 96 is in fluidcommunication with the proximate end 86 of the housing and with theaccess end 132 of the plunger 100 through said second fluid passage 150and the fluid duct 138 of the internal fluid bore 130. In the fluiddelivery-position, the medication is delivered from the pump assembly 28to the patient 12. In the fluid delivery-position, the first and thirdfluid connectors 94, 98 are isolated from the proximate end 86 of thehousing and from the access end 132 of the plunger 100 by the first andsecond seats 140, 142. However, the first and third fluid connectors 94,98 are in fluid communication with the reservoir 24 through the firstfluid passage 148 to supply the pump assembly 28 with the fluid, i.e.,with the medication. That is, in the fluid delivery-position, the firstand third fluid connectors 94, 98 are aligned with the first fluidpassage 148.

A fluid filling device, shown generally in FIG. 12B at 162, engages theproximate end 86 of the housing to automatically move the plunger 100into the fill-position for filling the reservoir 24 and the pumpassembly 28. If the system 10 is being sterilized, then the fluidfilling device 162 is preferably a fluid, or sterilization, cap 164(shown detached from the system 10 in FIG. 12B) that moves the plunger100 into the fill-position to enable a sterilization fluid to penetrateinto the reservoir 24 and the pump assembly 28. The fluid cap 164, bydesign, automatically moves the plunger 100 into the fill-position.Therefore, when the system 10 is introduced into a chamber filled withthe sterilization fluid, preferably EtO gas, then the sterilizationfluid flows, or seeps, through the fluid cap 164, through the proximateend 86 of the elongated housing 84 and the access end 132 of the plunger100, through the internal fluid bore 130 and the fluid duct 138, intothe second fluid passage 150, through the third fluid connector 98 intothe reservoir 24, and through the first fluid connector 94 into the pumpassembly 28.

When the system 10 is filled with medication, then the fluid fillingdevice 162 is preferably a syringe 166 that moves the plunger 100 intothe fill-position for filling the reservoir 24 and the pump assembly 28.The syringe 166 (shown attached to the system 10 in FIG. 12B) engagesthe access end 132 of the plunger 100 and, by design, automaticallymoves the plunger 100 into the fill-position for filling the reservoir24 and the pump assembly 28 through the internal fluid bore 130.Therefore, when the system 10 is being filled, the syringe 166 interactswith the proximate end 86 of the elongated housing 84 and the access end132 of the plunger 100 and, as the syringe plunger is depressed, themedication flows through the internal fluid bore 130 and the fluid duct138, into the second fluid passage 150, through the third fluidconnector 98 into the reservoir 24, and through the first fluidconnector 94 into the pump assembly 28.

To deliver the medication to the patient 12, the system 10 is utilizedin combination with the infusion tube set 14. Referring back to FIG. 1A,the infusion tube set 14 includes a fluid end 168 and a patient end 170.The fluid end 168 of the tube set 14, through a delivery connector 172,engages the proximate end 86 of the elongated housing 84 and the accessend 132 of the plunger 100 to automatically move the plunger 100 intothe fluid delivery-position for delivering the medication to the patient12. Therefore, as shown in FIGS. 13A-13B, when the pump assembly 28 isoperating, the medication is drawn from the reservoir 24 through thethird fluid connector 98 into the port 82 at the first fluid passage148, and through the first fluid connector 94 into the pump inlet 32.The medication is then displaced out of the pump assembly 28 through thepump outlet 34, through the second fluid connector 96 into the port 82at the second fluid passage 150, through the fluid duct 138 and theinternal fluid bore 130 of the plunger 100, and out the access end 132of the plunger 100 at the fluid end 168 of the infusion tube set 14.From there, the medication flows through the infusion tube set 14, outthe patient end 170, and to the patient 12.

Referring back to FIG. 4, the system 10 further includes the electroniccontroller 118. The electronic controller 118 controls an amount of themedication that is to be delivered to the patient 12. The electroniccontroller 118 is mounted to the base housing 16, specifically to thetop housing 22 of the base housing 16. Furthermore, the electroniccontroller 118 remains mounted to the base housing 16 duringsterilization such that the entire system 10, including all mechanicalcomponents, the reservoir 24, and the electronic controller 118, issimultaneously sterilized. An electronic display 174 and at least onecontrol button 176 are mounted to the base housing 16. The electronicdisplay 174 and the control button 176 interact with the electroniccontroller 118 to control the amount of the medication to be deliveredto the patient 12. As with the electronic controller 118, the electronicdisplay 174 and the control button 176 also remain mounted to the basehousing 16 during sterilization.

The subject invention also provides a blockage detection system which isgenerally disclosed at 178 in FIGS. 15A-15B. The blockage detectionsystem 178 detects a blockage in the flow of the medication to thepatient 12. The blockage detection system 178 comprises the base housing16, the reservoir 24, the port 82, the pump assembly 28, the medicationoutlet tube 122, and the electronic controller 118. The blockagedetection system 178 also includes a detection film 180 which isdescribed below.

In the blockage detection system 178, the electronic controller 118 ismounted to the base housing 16 adjacent the outlet tube 122. The outlettube 122 is mounted to the base housing 16 and, as described above, isconnected between the pump assembly 28 and the port 82 to provide accessfor the medication to flow from the pump assembly 28 into the port 82and to the patient 12. The outlet tube 122 has a diameter that iscontractible and expandable between a normal condition (see FIG. 15A)and an expanded condition (see FIG. 15B). The diameter of the outlettube 122 contracts and expands in response to variations in pressurethat result from the flow of the medication from the reservoir 24through the pump assembly 28 into the port 82 and to the patient 12.

As disclosed in the Figures, the outlet tube 122 is mounted to the basehousing 16 via a support platform 182. That is, the support platform 182is mounted on the base housing 16 to support the outlet tube 122 on thebase housing 16. The support platform 182 includes at least one tubeslot 184. The at least one tube slot 184 houses the diameter of theoutlet tube 122. The outlet tube 122 is mounted in the tube slot 184such that at least a portion, not numbered, of the diameter of theoutlet tube 122 is exposed to the detection film 180.

The detection film 180 is disposed between the electronic controller 118and the outlet tube 122. The detection film 180 is in contact with theoutlet tube 122 and remains spaced from the electronic controller 118when the diameter of the outlet tube 122 is in the normal condition, asin FIG. 15A. On the other hand, the detection film 180 is in contactwith the outlet tube 122 and contacts the electronic controller 118 toactivate the electronic controller 118 when the diameter of the outlettube 122 is in the expanded condition, as in FIG. 15B, in response toincreased pressure resulting from the blockage in the flow of themedication to the patient 12. More specifically, it is preferred that anelectronic switch 186 is embedded in the electronic controller 118between the electronic controller 118 and the detection film 180. Thedetection film 180 interacts with the electronic controller 118 bycontacting the electronic switch 186 to activate the electroniccontroller 118 when the diameter of the outlet tube 122 is in theexpanded condition.

For activating the electronic controller 118 when the diameter of theoutlet tube 122 is in the expanded condition, it is also preferred thatthe detection film 180 is conductive. Once activated by the detectionfilm 180, the electronic controller 118 deactivates the pump assembly 28to prevent delivery of the medication to the patient 12 when thediameter of the outlet tube 122 is in the expanded condition.Deactivation of the pump assembly 28 prevents further blockage andfurther increases in pressure. To properly ensure that the there is ablockage in the outlet tube 122, it is most preferred that theelectronic controller 118, and therefore the pump assembly 28, aredeactivated only if the diameter of the outlet tube 122 is in theexpanded condition for more than at least one cycle of the pump assembly28. This additional measure avoids false readings and the deactivationof the pump assembly 28 when the outlet tube 122 is truly not blocked.

Additionally, once activated by the detection film 180, the electroniccontroller 118 may also activate an alarm 188, shown schematically inthe Figures. The alarm 188, which can be audible and/or visuallydisplayed on the electronic display 174, would indicate the blockagethat is due to the blockage in the flow of the medication to the patient12.

It is preferred that the detection film 180 is mounted to the electroniccontroller 118. Although the detection film 180 is mounted to theelectronic controller 118, a portion, not numbered, of the detectionfilm 180 remains at least partially-spaced from the electroniccontroller 118 when the diameter of the outlet tube 122 is in the normalcondition. The detection film 180 is mounted to the electroniccontroller 118 with an adhesive layer 190. The adhesive layer 190 alsoestablishes a thickness that is necessary to space the detection film180, specifically the portion of the detection film 180, from theelectronic controller 118 when the diameter of the outlet tube 122 is inthe normal condition. The portion of the detection film 180 contacts theelectronic controller 118 to activate the electronic controller 118 whenthe diameter of the outlet tube 122 is in the expanded condition inresponse to increased pressure in the outlet tube 122.

An alternative embodiment for the blockage detection system 178 isdisclosed in FIG. 17. In this alternative embodiment, the detection film180 is eliminated, and a coating 192 is included. The coating 192 isapplied to the outlet tube 122. The coating 192 activates the electroniccontroller 118 when the diameter of the outlet tube 122 is in theexpanded condition in response to increased pressure resulting from theblockage in the flow of the medication to the patient 12. As with thedetection film 180, the coating 192 is preferably conductive. If thecoating 192 is present, it is most preferred that the coating 192 isformed of conductive carbon. However, other coatings may be used thatimpart conductive properties to the coating 192.

For the most part, the other characteristics of this alternativeembodiment for the blockage detection system 178 are identical to thecharacteristics that were described above in the preferred embodimentfor the blockage detection system 178. Notably, the outlet tube 122 ismounted in the tube slot 184 in this alternative embodiment such that atleast a portion of the coating 192 is exposed beyond the tube slot 184.

The subject invention also provides an empty detection system which isgenerally disclosed at 194 in FIGS. 16A-16B. The empty detection system194 determines when a supply of the medication has been depleted. Theempty detection system 194 comprises the base housing 16, the reservoir24 for storing the supply of the medication to be delivered to thepatient 12, the port 82, the pump assembly 28, the medication inlet tube120, and the electronic controller 118. As with the blockage detectionsystem 178, the preferred embodiment of the empty detection system 194also includes a detection film, also numbered 180, which is describedbelow.

In the empty detection system 194, the electronic controller 118 ismounted to the base housing 16 adjacent the inlet tube 120. The inlettube 120 is mounted to the base housing 16 and, as described above, isconnected between the reservoir 24 and the pump assembly 28 to provideaccess for the medication to flow from the reservoir 24 into the pumpassembly 28 and to the patient 12. The inlet tube 120 has a diameterthat is contractible and expandable between a normal condition (see FIG.16A) and a collapsed condition (see FIG. 16B). The inlet tube 120contracts into the collapsed condition and expands from the collapsedcondition into the normal condition. The diameter of the inlet tube 120contracts and expands in response to variations in pressure that resultfrom a lack of the flow of the medication from the reservoir 24 throughthe pump assembly 28 and to the patient 12.

As disclosed in the Figures, the inlet tube 120 is mounted to the basehousing 16 via the support platform 182. That is, the support platform182 is mounted on the base housing 16 to support the inlet tube 120 onthe base housing 16. The support platform 182 includes the at least onetube slot 184. The at least one tube slot 184 houses the diameter of theinlet tube 120. The inlet tube 120 is mounted in the tube slot 184 suchthat at least a portion of the diameter of the inlet tube 120 is exposedto the detection film 180.

The detection film 180 is disposed between the electronic controller 118and the inlet tube 120. As shown in FIG. 16A, the detection film 180 isin contact with the inlet tube 120 and contacts the electroniccontroller 118 to activate the electronic controller 118 when thediameter of the inlet tube 120 is in the normal condition. On the otherhand, as shown in FIG. 16B, the detection film 180 becomes spaced fromthe electronic controller 118 to deactivate the electronic controller118 when the diameter of the inlet tube 120 is in the collapsedcondition in response to the lack of flow of the medication that resultsfrom the supply of the medication being depleted.

It is preferred that an electronic switch 186 is embedded in theelectronic controller 118 between the electronic controller 118 and thedetection film 180. The detection film 180 contacts the electronicswitch 186 to activate the electronic controller 118 when the diameterof the inlet tube 120 is in the normal condition, and the detection film180 becomes spaced from the electronic switch 186 to deactivate theelectronic controller 118 when the diameter of the inlet tube 120 is inthe collapsed condition.

As best disclosed in FIG. 4, the detection film 180 more specificallyincludes a film base portion 196 and a cantilever portion 198. The filmbase portion 196 of the detection film 180 is mounted to the electroniccontroller 118 away from the electronic switch 186, and the cantileverportion 198 of the detection film 180 is adjacent the electronic switch186. More specifically, the cantilever portion 198 extends from the filmbase portion 104 to contact the electronic switch 186 when the diameterof the inlet tube 120 is in the normal condition. It is the cantileverportion 198 of the detection film 180 that becomes spaced from theelectronic controller 118 to deactivate the electronic controller 118when the diameter of the inlet tube 120 is in the collapsed condition.For activating the electronic controller 118 when the diameter of theinlet tube 120 is in the normal condition, it is also preferred that thedetection film 180, specifically the cantilever portion 198 of thedetection film 180, is conductive. Preferably, the detection film 180 ismounted to the electronic controller 118 with an adhesive layer 190. Ofcourse, it is the film base portion 196 of the detection film 180 thatis directly mounted to the electronic controller 118. The cantileverportion 198 of the detection film 180 is not directly mounted, orotherwise adhered, to the electronic controller 118 such that thisportion of the detection film 180 can become spaced from the electroniccontroller 118 when the diameter of the inlet tube 120 is in thecollapsed condition.

Once the detection film 180 becomes spaced from the electroniccontroller 118, i.e., when the diameter of the inlet tube 120 is in thecollapsed condition, the portion of the electronic controller 118 thatinteracts with the pump assembly 28 is deactivated such that the pumpassembly 28 is deactivated. Deactivation of the pump assembly 28 afterit has been determined that the supply of the medication has beendepleted prevents a build up of air in the system. To properly ensurethat the supply of the medication has been depleted, it is mostpreferred that the electronic controller 118, and therefore the pumpassembly 28, are deactivated only if the diameter of the inlet tube 120is in the collapsed condition for more than at least one cycle of thepump assembly 28. This additional measure avoids false readings and thedeactivation of the pump assembly 28 when the supply of the medicationis truly not depleted.

Additionally, deactivation of the portion of the electronic controller118 that interacts with the pump assembly 28 may also cause theelectronic controller 118 to activate the alarm 188. The alarm 188,which can be audible and/or visually displayed on the electronic display174, would indicate the lack of flow of the medication when the diameterof the inlet tube 120 is in the collapsed condition due to the lack offlow of the medication to the patient 12.

An alternative embodiment for the empty detection system 194 isdisclosed in FIG. 17. In this alternative embodiment, the detection film180 is eliminated, and the coating 192 is included. The coating 192 isapplied to the inlet tube 120. The coating 192 contacts the electroniccontroller 118 to activate the electronic controller 118 when thediameter of the inlet tube 120 is in the normal condition. On the otherhand, the coating 192 becomes spaced from the electronic controller 118to deactivate the electronic controller 118 when the diameter of theinlet tube 120 is in the collapsed condition in response to the lack offlow of the medication resulting from the supply of the medication beingdepleted. As with the detection film 180, the coating 192 is preferablyconductive. If the coating 192 is present, it is most preferred that thecoating 192 is formed of conductive carbon. However, other coatings maybe used that impart conductive properties to the coating 192.

For the most part, the other characteristics of this alternativeembodiment for the empty detection system 194 are identical to thecharacteristics that were described above in the preferred embodimentfor the empty detection system 194. Notably, the inlet tube 120 ismounted in the tube slot 184 in this alternative embodiment such that atleast a portion of the coating 192 is exposed beyond the tube slot 184.

Referring now to FIGS. 1B, 6A-6D, and 18A-18B, the system 10 of thesubject invention can be tested using a testing instrument 200 afterassembly of the system 10. The system 10 is tested after assembly andprior to shipment and use by the surgeons, patients, and the like toconfirm various operations of the system 10. In the preferredembodiment, to test the system 10, the system 10 is mounted onto thetesting instrument 200. One operation of the system 10 that is confirmedafter assembly of the system 10 is the operation of the pump assembly28.

To confirm these operations, the system 10 includes at least one testingaccess port 202. The at least one testing access port 202 is definedwithin the base housing 16 and is aligned with at least one of the pumpinlet 32, the pump outlet 34, and the actuator 102. Preferably, the atleast one testing access port 202 is aligned with all three of the pumpinlet 32, the pump outlet 34, and the actuator 102. The at least onetesting access port 202 provides access for the testing instrument 200to move the actuator 102 between the disengaged position and the engagedposition. If the at least one testing access port 202 is aligned withthe pump inlet 32 and the pump outlet 34 then it is aligned with thefirst and second pinch levers 38, 40, respectively. Also, as for thealignment with the actuator 102, the at least one testing access port202 is more specifically aligned with the at least one engagement arm106 of the actuator 102. This provides access for the testing instrument200 to move the actuator 102 between the disengaged position and theengaged position.

The system 10 is preferably assembled with the actuator 102 in theengaged position such that the first and second pinch levers 38, 40 arein the open position and the resiliency and life of the medication inletand outlet tubes 120, 122 is not compromised. Because the at least onetesting access port 202 provides access for the testing instrument 200to move the actuator 102 between the disengaged position and the engagedposition, the testing instrument 200 can be inserted into the at leastone testing access port 202 to disengage the actuator 102, i.e., to movethe actuator 102 into the disengaged position. As such, the pump inlet32 and the pump outlet 34 can alternate between the open and closedstates after assembly and during testing of the system 10.

The at least one testing access port also provides access for thetesting instrument 200 such that the pump inlet 32 and the pump outlet34 can be retained in the open state after the system 10 has been testedto prepare the system 10 for sterilization. That is, after the system 10has been tested, the actuator 102 is moved from the disengaged positionback into the engaged position to prepare the system 10 forsterilization. In the engaged position, the first and second pinchlevers 38, 40 are retained in the open state.

In the preferred embodiment, the at least one testing access port 202 isfurther defined as first, second, and third testing access ports 204,206, 208, respectively. The first testing access port 204 is alignedwith the pump inlet 32, the second testing access port 206 is alignedwith the pump outlet 34, and the third testing access port 208 isaligned with the actuator 102 for providing access to the testinginstrument 200 to move the actuator 102 into the engaged position. Morespecifically, the first testing access port 204 is aligned with thefirst pinch lever 38 such that the first pinch lever 38 is engaged bythe testing instrument 200. Once inside the first testing access port204, the testing instrument 200 forces the first pinch lever 38 awayfrom the pump inlet 32 and forces the pump inlet 32 into the open state.Similarly, the second testing access port 206 is aligned with the secondpinch lever 40 such that the second pinch lever 40 is engaged by thetesting instrument 200. Once inside the second testing access port 206,the testing instrument 200 forces the second pinch lever 40 away fromthe pump outlet 34 and forces the pump outlet 34 into the open state.The first and second pinch levers 38, 40 include the lever guides 78opposite the cam follower 76 of each pinch lever 38, 40. To move thefirst and second pinch levers 38, 40, the testing instrument 200 engagesthe lever guides 78 upon insertion into the first and second testingaccess ports 204, 206. After the testing instrument 200 forces the firstand second pinch levers 38, 40 away from the pump inlet 32 and the pumpoutlet 34, respectively, the testing instrument 200 is introduced intothe third testing access port 208 and the actuator 102 is moved into theengaged position to engage and retain the pinch levers 38, 40 in theopen position such that the system 10 is now prepared for sterilization.It is to be understood by those skilled in the art that the testinginstrument 200 includes male prongs, generally indicated at 210, thatare introduced into the testing access ports 204, 206, 208.

The system 10 further includes at least one controller access port 212defined within the base housing 16. In the preferred embodiment, the atleast one controller access port 212 is defined within the top housing22 or cover. The at least one controller access port 212 is aligned withthe electronic controller 118 to provide access for a second testinginstrument 214. It is to be understood that the second testinginstrument 214 and the testing instrument 200 may be a unitarycomponent, as disclosed in the Figures. The second testing instrument214 causes the electronic controller 118 to activate the motor 42 suchthat the motor 42 is powered to alternate the pump inlet 32 and the pumpoutlet 34 between the open and closed states after assembly and duringtesting of the system 10. The second testing instrument 214 alsopreferably includes male prongs 210 that are introduced into thecontroller access ports 212.

Referring primarily to FIGS. 2A-3, and 19-20, the system 10 of thesubject invention is also suitable to be carried by the patient 12. Tofacilitate carrying of the system 10 so the patient 12 can remainambulatory, a carrying strap 216 is mounted within the base housing 16for the carrying of the system 10 by the patient 12. An integral storagecavity 218 is defined within the base housing 16. The carrying strap 216is at least partially disposed in the integral storage cavity 218. Thecarrying strap 216 at least partially extends from the integral storagecavity 218 to interact with the patient 12 for carrying the system 10.

The system 10 further includes a plurality of cavity walls. The cavitywalls extend from the bottom housing 18 to define the integral storagecavity 218 between the bottom 18 and top 22 housings. Referringparticularly to FIG. 20, the cavity walls are further defined as a frontwall 220, a rear wall 222, and first and second side walls 224 extendingbetween the front and rear walls 220, 222 to support the front and rearwalls 220, 222 and to define the integral storage cavity 218. At leastone strap slot 226 is defined within the front wall 220 such that atleast a portion, not numbered, of the carrying strap 216 extends fromthe integral storage cavity 218 and through the strap slot 226. Thepatient 12 can then access the portion of the carrying strap 216 whendesired.

In interacting with the carrying strap 216, the patient 12 simplymanipulates, or grabs, the portion of the carrying strap 216 to pull alength of the carrying strap 216 from the integral storage cavity 218.This length is then looped about the head of the patient 12 asspecifically disclosed in FIG. 19. In the preferred embodiment, thecarrying strap 216 is retractable into the integral storage cavity 218after the length has been pulled from the integral storage cavity 218 bythe patient 12. The system 10 further includes a clip 228 that connectsopposing ends of the carrying strap 216 such that the carrying strap 216is adjustable to fit patients 12 of all sizes. In the most preferredembodiment of the subject invention, which is disclosed in FIG. 19, thecarrying strap 216 is further defined as a shoulder strap. The shoulderstrap suspends from a shoulder of the patient 12 for carrying the system10.

Also, as particularly disclosed in FIG. 1B, the system 10 may alsofurther include a system mounting clip 230 that extends from an exteriorfacing 232 of the base housing 16. The system mounting clip 230 can bemounted to a belt 234 of the patient 12. Of course, it is to beunderstood that the system mounting clip 230 is not to be limited to aclip for a belt 234. Instead, the system mounting clip 230 may bemounted to a shirt, a pocket, and the like.

Referring to FIGS. 2B, and 21-24, the subject invention further providesa method of controlling the system 10. This method is designed to beconvenient for both the surgeon, or other medical professional, and thepatient 12. A patient label 236, having a second set of explanatoryindicia, i.e., instructions, is mounted, preferably adhered, to thesystem 10. A removable overlay label 238, having a first set ofexplanatory indicia, i.e., instructions, is mounted, preferably adhered,to the patient label 236 to at least partially cover the patient label236.

The method includes the steps of selecting the amount of the medicationin accordance with the first set of explanatory indicia on the removableoverlay label 238. The medical professional selects the amount of themedication. As such, the first set of explanatory indicia is intended tobe readily understood by the medical professional. Typically, the amountof the medication is selected by selecting the flow rate for themedication. Other parameters including, but not limited to, the bolusamount, the drug or medication concentration, and like, can also beselected.

Throughout the step of selecting, the medical professional and/orpatient 12 interfaces with the electronic display 174 to view his or herselections. More specifically, the electronic display 174 presents areadable output for the medical professional and the patient 12. Thereadable output displayed on the electronic display 174 is correlatedwith the removable overlay label 238 and the patient label 236. That is,the readable output is correlated to the first and second sets ofinstructions. A first readable output is presented on the electronicdisplay 174. The first readable output is linked with the first set ofexplanatory indicia when the removable overlay label 238 is displayed.Similarly, a second readable output is presented on the electronicdisplay 174. The second readable output is linked with the second set ofexplanatory indicia after the system 10 has been locked. Locking thesystem 10 is described immediately below.

After the amount of the medication has been selected, the system 10 islocked such that selected amount of the medication to be delivered tothe patient 12 is unable to be modified. After the medical professionalis satisfied with his or her selection, the medical professionaldepresses the “LOCK” portion of the first set of explanatory indicia onthe removable overlay label 238 to lock the system 10.

Once the system 10 is locked, either the medical professional or thepatient 12 can remove the removable overlay label 238 to reveal thepatient label 236 (as shown in FIG. 21). To accomplish this, the user,either the medical professional or the patient 12, simply pulls theremovable overlay label 238 off the patient label 236. This reveals thecontrol button 176 that was originally masked under the removableoverlay label 238. The system 10 is then operated in accordance with asecond set of explanatory indicia on the patient label 236. The secondset of explanatory indicia is intended to be readily understood by thepatient 12. Once the system 10 is locked, the system 10 is designed tobe convenient for use by the patient 12.

Upon locking the system 10, a functionality of the control button 176 ismodified. As such, the functionality of the control button 176 isdifferent when the removable overlay label 238 is displayed on thesystem 10 as compared to when the patient label 236 is displayed on thesystem 10. In other words, the functionality of the control button 176is different when the medical professional interacts with the system 10via the removable overlay label 238 as compared to when the patient 12interacts with the system 10 via the patient label 236. When theremovable overlay label 238 is displayed on the system 10, the controlbutton 176 is at least tri-functional. On the other hand, after thesystem 10 has been locked and the patient label 236 is displayed on thesystem 10, the functionality of the control button 176 is converted frombeing at least tri-functional to being bi-functional.

In operating the system 10, the system 10 may be deactivated, ifnecessary, to stop delivery of the medication to the patient 12. Todeactivate the system 10, the patient 12 depresses the “ON/OFF” portionof the, now bi-functional, control button 176 in response to the secondset of explanatory indicia on the patient label 236. If the system 10 isdeactivated, then the patient 12 may also use the control button 176 toactivate the system 10 to re-start delivery of the medication to thepatient 12. To accomplish this, the patient 12 depresses the “ON/OFF”portion of the control button 176 again.

Alternatively, in operating the system 10, the patient 12 may request anadditional amount of the medication relative to the selected amount ofthe medication, and provided the Bolus amount will not be violated, thepatient 12 will receive an additional amount of the medication. Torequest an additional amount of the medication relative to the selectedamount, the patient 12 actuates the control button 176.

With specific reference to FIG. 25, a control system 240 for the system10, according to an embodiment of the present invention is shown. Thecontrol system 240 includes the electronic controller 118 and a motorcontrol circuit 242. The electronic controller 118 controls operation ofthe system 10 as described above.

In one embodiment, the electronic controller 118 includes amicroprocessor 244. One suitable microprocessor 244 is available fromPhilips Semiconductor of Sunnyvale, Calif. as model no. 87LPC764. Theelectronic controller 118 is programmed to control operation of themotor control circuit 242 with a computer software program. In general,the electronic controller 118 generates control signals in accordancewith the computer software program and delivers the control signals tothe motor control circuit 242.

The motor control circuit 242 includes a first switch 246. The firstswitch 246 has an open state and a closed state.

The control system 240 also includes a watchdog circuit 248 coupled tothe electronic controller 118. The watchdog circuit 248 includes amonitor circuit 250 and a second switch 252. The second switch 252 hasan open state and a closed state and is coupled to the first switch 246.The monitor circuit 250 is adapted to detect an abnormal condition ofthe control system 240 and to turn the second switch 252 off if theabnormal condition is detected. Examples of an abnormal conditioninclude, but are not limited to, too many revolutions of the motor 42,failure of the electronic controller 118, failure of the first switch246, or failure of a motor sensor 254 (see below).

The motor control circuit 242 is adapted to receive control signals fromthe electronic controller 118 and to responsively supply power to themotor 42 by placing the first switch 246 in the closed state. Power issupplied to the motor 42 if the first and second switches 246, 252 arein the closed state.

With reference to FIGS. 26 and 27, in one embodiment the first andsecond switches 246, 252 are field effect transistors (FETs) 256, 258.

In one embodiment, the control system 240 includes the control buttons176. A user such as the surgeon or the patient 12 is able to program thecontrol system 240 to deliver medication at the desired flow rate. Basedon the desired flow rate, the electronic controller 118 controlsenergization of the motor 42 to deliver the medication.

In one embodiment, each revolution of the motor 42 delivers a set amountof the medication during a known period of time. In order to meet thedesired flow rate, the electronic controller 118 calculates a period oftime between revolutions of the motor 42.

In one embodiment, the motor control circuit 242 includes the motorsensor 254 (see FIG. 4). The motor sensor 254 is coupled to the motor 42and is adapted to detect a revolution of the motor 42 and toresponsively generate a motor revolution signal in response tocompletion of the motor 42 revolution. In one embodiment, the motorsensor 254 is a opto-coupler sensor which is adapted to detect thepresence of an indicating flag 260 (see FIG. 5) connected to the motor42. The indicating flag 260 extends from one of the first and secondoutside cams 64, 66 to assist in monitoring the amount of the medicationthat has been delivered to the patient 12. The sensor 254 isoptically-coupled with the indicating flag 260 to count revolutions ofthe indicating flag 260. One suitable sensor 254 is available from Omronof Schaumburg, Ill., as model no. EE-SX1109.

In one embodiment, the electronic controller 118 is adapted to reset thewatchdog circuit 248 prior to sending control signals to the motor 42control circuit to energize the motor 42. The watchdog circuit 248 isadapted to place the second switch 252 in the opened state if two motorrevolution signals are received without the watchdog circuit 248 beingreset.

In other words, the electronic controller 118 must reset the watchdogcircuit 248 prior to or between each revolution of the motor 42. Thus,if a failure of the electronic controller 118 or the microprocessor 244erroneously causes a control signal to be delivered to the motor controlcircuit 242 to continuously place the first switch 246 in the closedstate, and thus, to erroneously energize the motor 42, the second switch252 will be placed in the opened state. With the second switch 252 inthe opened state, power will not be delivered to the motor 42.

Additionally, if a failure of the first switch 246 leaves the firstswitch 246 in the closed state, successive motor revolution signals willbe received by the watchdog circuit 248 without the watchdog circuit 248being reset and the watchdog circuit 248 will place the second switch252 in the opened state, thus preventing power from being supplied tothe motor 42.

In one embodiment, the electronic controller 118 is adapted to track thetime after a motor control signal has been sent and to enter a disabledstate if the time between the sent control signal and received motorrevolution signal exceeds a predetermined threshold.

With specific reference to FIG. 26, in one embodiment the monitorcircuit 248 includes first and second flip-flops 262, 264. The firstflip-flop 262 is coupled to the electronic controller 118 and the secondflip-flop 264. The second flip-flop 264 is coupled to the second FET258.

In the illustrated embodiment, the first and second flip-flops 262, 264are JK flip-flops. The inverse output (Q) of the second flip-flop 264 isconnected to the gate of the second FET 258. The clock input (CLK) ofthe second flip-flop 264 is coupled to the output (Q) of the firstflip-flop 262. Power is supplied by the microprocessor 244 to the firstand second flip-flops 262, 264 to the J and K inputs of the first flop262 and to the J input of the second flip-flop 264. The drain of thesecond FET 258 is coupled to the first FET 256 and the source of thesecond FET 258 is connected to electrical ground.

The watchdog circuit 248 is reset by shutting off and restoring power tothe first and second flip-flops 262, 264, to the J and K inputs of thefirst flop 262, and to the J input of the second flip-flop 264. In oneembodiment, the electronic controller 118 shuts off power to the firstand second flip-flops 262, 264 after each revolution of the motor 42 andsupplies power prior to turning on the first switch 246 to begin thenext cycle. This has two effects: conserving power and resetting thefirst and second flip-flops 262, 264.

The clock input (CLK) of the first flip-flop 262 is connected to theoutput of the motor sensor 254. The clock input (CLK) of the firstflip-flop 262 is also connected to the microprocessor 244 via a thirdFET 266. The third FET 266 provides isolation between the microprocessor244 and the motor sensor 254 and the monitor circuit 248. This isolationprevents a shorted pin on the electronic controller 118 from preventingrevolution pulses from reaching the flip-flops 262, 264.

The inverse clear input ( CLR) of the first and second flip-flops 262,264 are coupled to the microprocessor 244 via a buffer circuit 268. Inthe illustrated embodiment, the buffer circuit 268 includes a firstbuffer 270, a first resistor 272 and a capacitor 274. The electroniccontroller 118 may continuous supply power to the motor 42 by turning onthe first switch 246 and continuously resetting the first and secondflip-flops 262, 264 through the inverse clear inputs without turning offpower to the flip-flops 262, 264.

In one embodiment, the flip-flops 262, 264 are triggered by logic levelhigh (“HIGH”) to logic level low (“LOW”) transitions. The buffer circuit268 prevents erroneous signal transitions when the input to the buffercircuit 268 is held HIGH by the microprocessor 244.

With specific reference to FIG. 27, the motor control circuit 242includes the first FET 256 and the opto-coupler sensor 276. A flashbackdiode 278 is coupled across first and second motor junctions 280A, 280B.The opto-coupler sensor 276 is coupled to the second motor junction280B. The transmitting diode of the opto coupler sensor 276 is coupledto power (V+) and ground through switch 256. In this arrangement thesensor 276 is only powered during the time the motor 42 is running thusconserving battery life. An output of the opto-coupler sensor 276 iscoupled to the third transistor 266 via a second buffer 282.

The gate of the first FET 256 is coupled to the microprocessor 244. Thedrain of the first FET 256 is coupled to the motor 42 and the source ofthe first FET 256 is connected to the drain of the second FET 258.

As described above, the electronic controller 118 is adapted to supplymedication by energizing the motor 42. A desired flow rate is achievedby energizing the motor 42 and waiting between revolutions of the motor42 for a calculated period of time. The motor 42 is energized by turningon the first FET 256. In the illustrated embodiment, the first FET 256is turned on by the microprocessor 244 by changing the state of the gateof the first FET 256 from LOW to HIGH. If the second FET 258 is also on,then power flows through the motor 42 and the first and second FETs 256,258. When the motor 42 has made one (1) complete revolution, then theoutput of the motor sensor 254 transitions from HIGH to LOW. In theillustrated embodiment, this transition is the motor revolution signal.The motor revolution signal is also transmitted to the microprocessor244 via the third FET 266. After receiving the motor revolution signalthe microprocessor 244 turns off the first FET 256 by changing the stateof the gate of the first FET 256 from HIGH to LOW.

During normal operation, the microprocessor 244 then turns off power tothe first and second flip-flops 262, 264. As described above, based onthe desired flow rate and the known quantity of medication delivered perrevolution of the motor 42, the microprocessor 244 calculates a waitperiod between motor revolutions. After the wait period (or right beforethe wait period ends), the microprocessor 244 restores power to thefirst and second flip-flops 262, 264. As discussed above, this resetsthe first and second flip-flops 262, 264. Then the microprocessor 244may again turn on the first FET 256 to energize the motor 42.

If a failure condition of the control system 240 exists, such as amicroprocessor 244 failure or other failure, and the watchdog circuit248 is not reset, then watchdog circuit 248 turns off the second FET258, thereby preventing power from being supplied to the motor 42.

For example, if the microprocessor 244 fails while the first FET 256 ison, then the motor 42 will continue to be energized. The motor sensor254 will generate motor revolution signals each time a motor revolutionis completed. However, the microprocessor 244 does not or is unable toreset the watchdog circuit 248. Two successive motor revolution signalsreceived on the CLK input of the first flip-flop 262 without thewatchdog circuit 248 being reset will flip the inverse output of thesecond flip-flop 264 (from HIGH to LOW) and thus turn off the second FET258.

Likewise, a failure of the first transistor 256 in the closed state willcontinuously energize the motor 42. If the microprocessor 244 does notreset the watchdog circuit 248, then successive motor revolution signalsreceived on the CLK input of the first flip-flop 262 will flip theinverse output of the second flip-flop 264 and thus turn off the secondFET 258.

With the second FET 258 in the off state, power will not be delivered tothe motor 42.

Returning to FIG. 25, the control system 240 further includes a key 284which is connected to the electronic controller 118 only duringinitialization. In one embodiment, the key 284 is part of the testinginstrument 200 which is also used to test the control system 240 afterit has been assembled and the batteries 45 are installed. Upon initialpower-up, the control system 240 will only initialize if the key 284 ispresent. If the key 284 is not present, then the control system 240enters a disabled mode and medication cannot be delivered.

In one embodiment, upon initial power-up the control system 240 sends asignal to the key 284. If present, the key 284 delivers a return signalto the control system 240 indicating its presence. The use of the key284 ensures that the system 10 cannot be improperly reset by removingand then re-inserting the batteries 45 or other power supply 43. If thisoccurs and the key 284 is not present, the system 10 will not work.

The control system 240 includes a crystal 285 coupled to themicroprocessor 244. The crystal 285 controls the frequency at which themicroprocessor 244 operates in a conventional manner. However, if thecrystal 285 is operating improperly, the microprocessor 244 could beginto operate at either a higher frequency or a lower frequency thanintended. The microprocessor 244 also includes an internal oscillator286. In one embodiment, the control system 240 is adapted to compare afrequency of the crystal 285 with a frequency associated with theinternal oscillator 286. The electronic controller 118 adapted tocompare a difference between the first and second frequencies and entera disabled state if the difference is greater than a predeterminedthreshold. Thus, if the crystal 285 experiences a failure, the controlsystem 10 will be disabled.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is, therefore, to beunderstood that reference numerals are merely for convenience and arenot to be in any way limiting, the invention may be practiced otherwisethan as specifically described.

1. A method of controlling a medication delivery system that is used todeliver medication to a patient wherein the system includes anelectronic controller, at least one control button, a patient label, anda removable overlay label disposed on top of the patient label forcontrolling an amount of the medication to be delivered to the patient,said method comprising the steps of: selecting the amount of themedication in accordance with a first set of explanatory indicia on theremovable overlay label; locking the system such that the selectedamount of the medication to be delivered to the patient is unable to bemodified; removing the removable overlay label to reveal the patientlabel; and operating the system in accordance with a second set ofexplanatory indicia on the patient label.
 2. A method as set forth inclaim 1 wherein the step of operating the system in accordance with thesecond set of explanatory indicia comprises the step of deactivating thesystem to stop delivery of the medication to the patient.
 3. A method asset forth in claim 2 wherein the step of operating the system inaccordance with the second set of explanatory indicia further comprisesthe step of activating the system to re-start delivery of the medicationto the patient after the system has been deactivated.
 4. A method as setforth in claim 1 wherein the step of operating the system in accordancewith the second set of explanatory indicia comprises the step ofrequesting an additional amount of the medication relative to theselected amount.
 5. A method as set forth in claim 4 wherein the step ofrequesting an additional amount of the medication relative to theselected amount is further defined as actuating the control button torequest the additional amount of the medication.
 6. A method as setforth in claim 1 wherein the step of selecting the amount of themedication is further defined as selecting a flow rate for themedication.
 7. A method as set forth in claim 1 wherein the step oflocking the system comprises the step of modifying a functionality ofthe control button such that the functionality of the control button isdifferent when the removable overlay label is displayed on the system ascompared to when the patient label is displayed on the system.
 8. Amethod as set forth in claim 7 wherein the control button is at leasttri-functional when the removable overlay label is displayed on thesystem and the step of modifying the functionality of the control buttonis further defined as converting the functionality of the control buttonfrom at least tri-functional to bi-functional after the system has beenlocked and the patient label is displayed on the system.
 9. A method asset forth in claim 1 wherein the system further includes an electronicdisplay that presents a readable output and said method furthercomprises the step of correlating the readable output of the electronicdisplay with the removable overlay label and the patient label.